[EDIT] I read a few articles on the subject, and the cutter head lifting is only mentioned on small planers. They contend a locking head will prevent the problem. Every other article talks about feed roller pressure and how close to cutterhead. Explains why lifting a board works, but doesn't explain how feeding another board right behind works - that seems supported by the lifting cutterhead idea.[/edit]
Its a really interesting discussion but the physics still escape me - relative to a cast iron planer. I'll take what you guys say as a fact, even though I still can't understand how a roller head mounted in a cast iron head is going to flex upward. I'm trying to correlate to using a hand plane but can't.
As I mentioned, I get zero snipe on my planer. I attribute this to the fact it has a pressure bar which I believe most planers do not have, correct me if I'm wrong.
It also has bed locking knobs, which I never use, and I'm not aware of many planers that have them. I have seen my height adjustment wheel rotate as wood goes through on a heavy pass. It has never done this before the last year. For me, I take that (plus noise) as an indication the blades are dull, but also seems to support what Rick is saying.The blades are WAY over due.
So question: does blade sharpness come into play? Seems like there would be less down force if the knives are sharp.
What I do know is a long board hanging off the outfeed will have snipe regardless, and when planing thin stock a slight uplift on both infeed and outfeed eliminates issues. I had some snipe, but lowering the bed rollers below the bed totally eliminated it. Me, my planer, and 20 years experience using it.
So I think there are a few causes of snipe, maybe all of us are right in one way or another. In the end, all that matters is good results, not understanding why you're getting them?
Newer version of my machine:
